Are you talking 400crank hp or 400- 450whp? because there is a big difference 400 crank= 67hp per cylinder and is not unrealistic figure on stock internals and with a set of ARPs and a good tune you could get there for sure. Now if your talking 400whp-450whp your going to need to upgrade internals, drive shaft, LSD, brakes, fluids, fuel pump ect. takes alot of money to get to a reliable 450whp !!

400-450 crank is good enough..i was thinking about boosting/turboing it a month before winter and play around with the boost. that way if i damage or destroy my motor..id have 5 months to reasearch and build the shit outta it..